Rust 1.88 Demotes i686-pc-windows-gnu to Tier 2

Rust 1.88.0 will demote the i686-pc-windows-gnu target (32-bit GNU-based Windows build target) from Tier 1 to Tier 2. This means reduced testing frequency and a higher likelihood of accumulating bugs in the future. The main reason is a lack of maintainers and persistent difficult-to-debug issues. While builds of the standard library and compiler will still be provided, users should be aware of potential increased risks. The Rust team is calling for developers with relevant expertise to step up and become maintainers.